1. COB and GOB LED Technologies
(1) COB LED Technology
COB, an acronym for "Chip-On-Board," translates to "chip packaging on the board." This technology directly adheres the bare light-emitting chips to the substrate using conductive or non-conductive adhesive, forming a complete module. This eliminates the need for chip masks used in traditional SMD packaging, thereby removing the physical spacing between chips.
(2) GOB LED Technology
GOB, short for "Glue-On-Board," refers to "gluing on the board." This innovative technology uses a new type of nano-scale filling material with high optical and thermal conductivity. It encapsulates traditional LED display PCB boards and SMD beads through a special process and applies a matte finish. GOB LED displays fill the gaps between beads, akin to adding a protective shield to the LED module, significantly enhancing protection. In summary, GOB technology increases the weight of the display panel while significantly extending its lifespan.
2. Advantages and Disadvantages of COB and GOB LED Technologies
GOB LED Screens
Advantages:
(1) Enhanced Shock Resistance: GOB technology provides LED displays with superior shock resistance, effectively mitigating damage from harsh external environments and significantly reducing the risk of breakage during installation or transportation.
(2) Crack Resistance: The adhesive's protective properties prevent the display from cracking upon impact, creating an indestructible barrier.
(3) Impact Resistance: The protective adhesive seal of GOB significantly reduces the risk of impact damage during assembly, transportation, or installation.
(4) Dust and Pollution Resistance: The board-gluing technique effectively isolates dust, ensuring the cleanliness and quality of GOB LED displays.
(5) Waterproof Performance: GOB LED displays feature waterproof capabilities, maintaining stability even in rainy or humid conditions.
(6) High Reliability: The design incorporates multiple protective measures to reduce the risk of damage, moisture, or impact, thereby extending the display's lifespan.
Disadvantages:
(1) Difficult to Repair: Repairing LEDs in GOB LED displays is challenging. Although the adhesive reduces impact damage, it complicates repairs.
(2) PCB Warping: High-stress adhesive can cause PCB warping, affecting the display's flatness.
(3) Thermal Degradation: Thermal expansion of the adhesive can lead to color changes and localized degumming.
(4) Secondary Image Issue: The adhesive covering the light-emitting surface may produce secondary optical images, affecting viewing quality.
(5) False Welding Problem: In the event of false welding, repairing GOB LED displays becomes extremely difficult.
COB LED Screens
Advantages:
(1) Compact Design: Chips are directly bonded, eliminating the need for additional lenses and packaging, significantly reducing size and saving space.
(2) Energy Efficiency: Higher light efficiency than traditional LEDs results in superior illumination.
(3) Improved Illumination: Offers more uniform illumination compared to traditional models.
(4) Optimized Heat Dissipation: Reduced heat generation from chips eliminates the need for additional cooling measures.
(5) Simplified Circuitry: Requires only one circuit, resulting in a more streamlined design.
(6) Low Failure Rate: Fewer solder joints decrease the risk of failure.
Disadvantages:
(1) Color Uniformity Issue: Light splitting between chips may cause uneven coloration in the display.
(2) Decreased Efficiency: As chip size increases, light and LED efficiency may decline.
(3) Limited Color Selection: The range of available colors is relatively limited, potentially not meeting all needs.
3. Differences Between COB and GOB Technologies
(1)Packaging Technology
The manufacturing process of COB LED displays involves directly attaching the 'light-emitting chips' to the PCB substrate, followed by coating them with a layer of epoxy resin to complete the packaging. This method primarily aims to protect the 'light-emitting chips.' In contrast, GOB LED displays form a protective layer by applying a transparent adhesive to the surface of the LED beads, with the primary focus on protecting the 'LED beads.'
COB technology focuses on protecting LED chips, while GOB technology provides additional protection for LED beads. Implementing GOB technology requires strict adherence to the specific requirements of LED display products, involving complex production processes, high-standard automated production equipment, and specialized materials for GOB LED displays. Customized molds are also necessary. After product assembly, GOB packaging requires a 72-hour aging test to inspect the beads before gluing, followed by another 24-hour aging test after gluing to ensure product quality. Therefore, GOB LED displays have extremely strict controls over material selection and process management.
(2)Applications
COB LED displays, by eliminating the physical spacing between LED beads, can achieve ultra-narrow pitch displays with pitches below 1mm, making them primarily used in the small-pitch display field. In contrast, GOB LED displays comprehensively enhance the protective performance of traditional LED displays, effectively resisting interference from harsh environments with multiple protective functions, including waterproofing, moisture-proofing, impact-proofing, dust-proofing, corrosion-proofing, blue light-proofing, and static electricity-proofing. This expands the application scope of LED displays.
